6 N. H. AGR. EXPERIMENT STATION. [Bulletin 160 



seem to represent all horn growth the Merino ewe is capable of 

 making, except in instances where the knob has disrupted the 

 skin and a scablike horn or scur has resulted. From an exam- 

 ination of 128 Class A and B American Merino ewes I discovered 

 53 individuals or 41 per cent, bearing knobs and five of these 

 had besides scabs or short scurs. In our Station flock of Merinos 

 which consists mostly of pure-bred Rambouillets with a few 

 heavily wrinkled Americans there is virtually as great a per- 

 centage of females with knobs. 



Horns of Merino rams are not always sufficiently developed 

 at birth so that they can be readily perceived or even felt. In 

 fact, several days may elapse before an appreciable growth is 

 made to enable an observer to recognize the presence of a horn. 

 This is not the case with the Dorset Horn or any breed where both 

 sexes bear horns. Horn growth with these sheep can almost 

 invariably be distinguished at birth. The length will vary from 

 a quarter to an inch and a half or even greater. The males have 

 more prominent horns at birth than the opposite sex. I have 

 been assured of these facts by sheep raisers and also by my own 

 practical experience with sheep. Darwin* remarked these con- 

 ditions, although in the case of the Merinos his evidence is 

 limited. However, he cites one striking instance, which, perhaps, 

 as Merinos are known in this country, represents an exception in 

 prolonged horn development rather than the rule, of a Merino 

 ram in Saxony, observed by Prof. Victor Carus, which was born 

 on Feb. 10 and first showed horns on March 6. 



Castration also affords most interesting data and brings forth 

 rather peculiar results in its effect on the development of horns. 

 Here again a divergence occurs between the two types of horns as 

 represented by the Merino and the Dorset Horn. Early castra- 

 tion of a Merino ram lamb leads to a wether, destitute, or almost 

 so, of horns. An emasculated Dorset, even though the testes are 

 removed when but two or three weeks old, always produces 

 horns, although these are reduced in size, and, according to my 

 observation and what I have been told by practical breeders of 

 these sheep, they correspond in length and diameter to about 

 two-titiirds of the size of the normal horn. Castle f (1911) has 

 noted the disappearance of horns in castrated Merino rams and 

 draws therefrom the conclusion that "the presence of the male 

 sex-gland in body, or rather probably some substance given off 

 into the blood from the sex-gland, favors the growth of horns." 

 Darwin $ (1871) also had considerable evidence, bearing on this 

 subject, which I quote: 



"With sheep both sexes properly bear horns; and I am in- 

 formed that with Welch sheep the horns of the males are consider- 



* Darwin, Charles, "The Descent of Man and Selection in Relation to Sex." New York- Appleton. 

 t Castle, W. E., "Heredity in Relation to Evolution and Animal Breeding." New York: Appleton. 

 j Darwin, Charlea, "The Descent of Man and Selection in Relation to Sex." New York, Appleton, 



